Epoxy resin masses and process for preparing them



Patented June 27, 1967 of epoxy resins mentioned above which contained the ,331 solvents generally used up to now. EPOXY i g gg gg FOR The rocess of the present invention is particularly ap- Guido Max Rudolf Lorentz, Oes Post Espa, near Butzplppriate in W i of epoxy rqsins which are bach, Werner Matheis, Schwalbach, Taunus, Heimut tamed by reactmg eplchlorohydnn Wlthi Neises, Keikheim, Taunus, and Rudolf Stroh, Hofheim, (1) 4 4-dihydroxy-2 Z-diphenyl pro pane bisphenolA 11: 5:52 ggggg x ifigg fi gs 33: 3:5 3222: (2) a condensation product of o-cresol and formaldehyde Frankfurt am Main, Germany a corporatiofi of which contains 90-95% of a product obtained by remany acting 2 mols of o-cresol and 1 mol of formaldehyde No Drawing. Filed Jan. 20, 1964, Ser. No. 338,623 phenolresins, paltlwlarly nvvolaks or Claims priority, application Germany, Jan. 22, 1963, allphatlc P Y Y Y COITIPOUHdS- 6 Claim: g 2 There are preferably used the resins obtained by the condensation of bisphenol A with epichlorohydrin and/ or The present i ve ti l t t epoxy resin masses 1,3-dich1orohydrin in the presence of alkalis, which have and to a process for preparing them. the following formula CH3 CH3 CH2CH-CHz[O(5-C -OCH;CHOH-OH ],,O( C O-CH2CHCH2 I l O CH; CH; O

Epoxy resins, i.e. reaction products from epichloro- In general it is advantageous to add the cyclic ethers hydrin and substances containing hydroxyl groups, prefused for the reduction of viscosity to the epoxy resin in erably bisphenol A, are viscous substances as far as they a quantity such that in 100 parts by weight of the mixare not solid bodies. However, for various technical purture composed of cyclic ether and epoxy resin 1-30 parts posesa lower viscosity of the resins is desired. This reby weight of the cyclic ether are contained. The most duction of the viscosity has hitherto been achieved by advantageous quantity of cyclic ether to be added can adding solvents, for example xylene, furfuryl alcohol, be determined without difiiculty by a preliminary test. acetone, ethyl acetate or chloroform, There are preferred mixtures containing in 100 parts by Particularly when using epoxy resins together with Weig t 5-20 parts by Weight ofthe cyclic eth r. fillers, i.e. generally silicates, and ha d b d on The excellent reduction of viscosity obtained by the polyamines, for preparing fleximer jointless flooring it is addition of cyclic ethers to epoxy resins is illustrated by necessary in order to achieve a better workability to add the following table: to the foundation material solvents, for example xylene, as REDUCTION OF VISCOSITY OF EPOXY RESINS diluents. Besides improving the workability the addition of solvents also makes it possible to add to the mass a Epoxy larger amount of the filler. After the hardening process Composition resin gi 'f z g y a considerable quantity of the diluent remains in the ii a an poms mass. However, the greater part of these solvent portions rgmanent 1n the mass gradually evaporates. It 18 possible 40 parts y weiggt re ox re m from 0. 545 26,500 at 20 C. t at hi Va 0 i ispheno Aan epic oro y rin.

S e p rat n tak S place i course of several 85 parts by weight oi epoxy resin, 15 0.545 600 at 20 C. months and even of 1 year, and it is easy to understand parts by weight ofxylene. that the period of time in which the solvent evaporates 90 Parts by Weight l resin 10 0-545 1180 parts by weight of trioxane. from the mass dfipends t0 8 large extent on The VHPOI s5 partsbby welilghtfot epoxy resin, 15 0. 545 090 at 20 0.

parts yweig to trloxane. pressure of the solvent. It is obvious that the evaporation 4o 80 parts by weight of epoxy resin 20 0. 545 420 at of solvents from the hardened mass involves a shrinkage parts by weightoftrioxane. which may gradually cause crack growth in the epoxy 85 Parts by Weight of epoxy resin 15 0-545 700 parts by weight of paracetaldehyde. resins. Besides the drawbacks that are due to the shrinkage i g byAwej%ht grlfl o l r551 from 0.33 52,300 at C.

1 bsp enol an epc oro 1y rin. of the mass calsed by the evaporation of the solvents, 80 parts by Weight of epoxy resin, 20 0'38 1,000 at hardened epoxy resin masses wh1ch had to be hardened 60 pans byweigmoimomm 1n the presence of a solvent also have an inferior resistance to chemicals and to solvents, an elevated thermal "Epoxy value=mols oi epoxy groups in 100 g. 01' resin. expansion and a reduced heat distortion point (Irving Skeist Epoxy Resins, page 33 (Reinhold Publishing For hardening the masses according to the present 1n- Corporation New York, 1959). vention there are used the polyamines generally applied Furthermore, the annoyances due to odour that are for.hard.enmg epoxy l example dlfathylene caused by the solvents and their toxic properties have ammeidlejthylene tnammemethylene tetramme extremely serious drawbacks in the working of epoxy ylelledlamme. hyclrogenated m phenylene dlamme resin masses containing volatile solvents. ammoetilylplper 3211,18 and polymers of Polyvaleni alkyl" NOW We have found that there can be obtained an ene amines according to German Auslegeschrift No. extremely important reduction of viscosity by adding to epoxy resins Cyclic ethers of the general formula The improvement of the mechanical properties and of the resistance to chemicals of the foundation materials that contain as diluent instead of a solvent the additive RHC CHR according to the present invention was determined by I means of testing bodies composed of a foundation material which contained as epoxy resin a condensation product of epichlorohydrin and bisphenol A having an epoxy value R of 0.545 and a viscosity (undiluted) of 26,500 centipoises in which R means a hydrogen atom or an alkyl group, 70 at 20 C., as hardener a polyamine having an amine preferably a methyl group, and that after the hardening qui e of 40 as filler, quartz Powder 0f the process these masses do not have the undesired properties lowing grain composition:

Percent 2-1 mm. 6 l0.75 mm. 19 075-03 mm. 9 0.3-0.15 mm. 26 0.15-0.1 mm. 0.1 mm.

There were used as diluents trioxane (trioxymethylene) and paraldehyde (trimethyl-trioxane). For reasons of comparison there are mentioned the values obtained when using testing bodies having the same basic composition, containing, however, xylene as diluent.

The testing bodies were stored at the air for 7 days at about 20 C. (room temperature) before the test.

For determining the resistance to chemicals the testing bodies obtained were refluxed for 8 hours in the liquids mentioned in the table then they were rinsed, dried in a drying chamber at 100 C., and then the difference in weight was determined by weighing.

The values obtained are indicated in the following table, the respective composition of the foundation materials being shown in the 1st column:

As isshown by the results indicated in Table 2, the

ber at C. The plate prepared with the addition of xylene already had numerous shrinkage cracks after 3 hours. The plate which was prepared with the addition of trioxane, however, could be stored for several hours, at 60 C. without appearance of damages. It was not even damaged or destroyed when heated to 100 C. for more than 1 week. When exposed to suddenly changed temperaturessthe plate showed an excellent stability which was such that it could be chilled from 100 C. to 15 C. by plunging it several times into cold water without its undergoing damages. Furthermore, practically no loss of weight could be observed after its exposure to the temperature treatment.

The dilution without solvents of epoxy resins with the compounds mentioned above is not only of interest as to the preparation of foundation material, but also when using epoxy resins as coating material, for impregnating processes and as casting resins; by impregnating processes there are meant in the first line the combinations of liquid epoxy resins with glass or asbestos fibres.

We claim:

1. In the reduction of the viscosity of epoxy resin the improvement which comprises adding a trioxane of the general formula TABLE 2 Tensile strength, kg. lcm. 2

Cornpressive strength, kg. cm.

HCl,

Composition NaO H, Acetone Benzene Gasoline Acetic acid Diesel 20% Epoxy resin (0.545 epoxy Value), 85 parts by weight, xylene, 15 parts by weight; polyarnine hardener, 21.25 parts by weight, quartz powder, 630 parts by weight Epoxy resin (0.545 epoxy value), 85 parts by weight, trioxane, 15 parts by weight; polyamine hardener, 21.25 parts by weight, quartz powder, 630 parts by welght Epoxy resin (0.545 epoxy value), 90 parts by weight, trioxane, 10 parts by weight; polyarnine hardener, 21.5 parts by weight, quartz powder. 630 parts by Weight Epoxy resin (0.545 epoxy value), parts by weight, trioxane, 20 parts by weight; polyamine hardener, 20 parts by weight, quartz powder, 630 parts by weight.

Epoxy resin (0.545 epoxy value), parts by weight; polyarnine hardener, 21.25 parts by weight, paraldehyde, 15 parts by weight, quartz powder, 630 parts by weight Resistance to chemicals indicated in percent of loss or increase or weight (determined by the method indicated above).

mechanical and chemical properties of epoxy resin masses are considerably improved by an addition of cyclic ethers. When using paracetaldehyde the improvement of the mechanical properties is inferior, but there are obtained also in this case masses that have a considerably increased resistance to chemicals. The optimum results were obtained by adding 10% of trioxane.

The use of the trioxane that is added according to the present invention instead of the solvents hitherto used for the reduction of viscosity of epoxy resins also has a favourable effect on the behaviour of the hardened resin when exposed to thermal stress as is illustrated by the following comparison test:

A mixture was prepared of 85 parts by weight of epoxy resin, 21.25 parts by weight of polyamine hardener and 15 parts by weight of diluent and there were used as epoxy resin and as hardener the same products as for carrying out the tests described above. As diluent there was used in one case xylene, in the other case trioxane (trioxymethylene).

This mixture was cast into plates of 30 x 30 x 0.5 cm. which were completely hardened in both cases after 24 hours.

The plates thus obtained were heated in a drying chamin which R represents a member selected from the group consisting of hydrogen and an alkyl group.

2. An epoxy resin composition comprising a liquid diglycidyl ether of polyhydric aromatic alcohols and as a viscosity reducer a trioxane of the general formula 5. A hardenable epoxy resin composition comprising a liquid diglycidyl ether of polyhydric aromatic alcohols, a trioxane as a viscosity reducer for said ether and an amine hardening agent.

6. A hardenable epoxy resin composition comprising a liquid diglycidyl ether of polyhydric aromatic alcohols and a trioxane as a viscosity reducer, said trioxane being of the formula 6 wherein R is a member selected from the group consisting of hydrogen and an alkyl, and a polyamine hardening agent.

References Cited UNITED STATES PATENTS 2,947,726 8/1960 Belanger 260-304 3,027,352 3/1962 Walling et a1 26067 3,050,474 8/1962 Russell 260-30.4 3,072,607 1/1963 Fisch et al. 26030.4

MORRIS LIEBMAN, Primary Examiner. J. E. CALLAGHAN, Assistant Examiner. 

1. IN THE REDUCTION OF THE VISCOSITY OF EPOXY RESIN THE IMPROVEMENT WHICH COMPRISES ADDING A TRIOXANE OF THE GENERAL FORMULA 